1) Yes, a test is affected by what was eaten in the two or three days before the tests so big swings are normal.
2) Only your doctor can answer that, but a statin can drop you TC by 42% so it's probably the reason your number is down.
3) Just keep up the diet end exercise and retest in about 6 months.
sn95, your Rx dose is pretty high. So it is possible that all the lifestyle change combined with med caused the significant drop. However, I just came back from my doctor's office who gave me a GI referral to check for potential liver disease. I had a LDL drop from 170s to 50s and TG increase from 100 to 200 during the same time, accompanied by abdominal pain, bloating, mid-back pain, fatigue, loss of appetite, weight loss, etc. I had fatty liver and liver cysts, which normally wouldn't cause many symptoms. But anytime a patient has significant cholesterol drop with various vague symptoms, a responsible physician should look into possible liver problems rather than assuming statin alone caused it. I wouldn't worry much though if you are asympthomatic.
It goes almost without saying that the most important thing you need to address is your smoking.
That single item will have more impact on your future health and disease than anything else.
You don't yet have a good picture of your cholesterol readings given that you were put on a fairly high dose of Lipitor right of the bat.
I'm curious, you mention you changed your diet, and then you said you did a "serious" change of diet before your last test.
What does that mean?
A serious change of diet for those wanting to avoid Lipitor for the next 50 years (33 to 83) would be more along the lines of what former president Bill Clinton finally did to prevent further heart disease.
Also, if you were willing to make such a change, it may take more than 25 days for the full effect. Much of that recent change you got was probably from the 40 mg dose of Lipitor.
So I'm wondering what you mean by a "serious" change in diet?
Many people can get competely off Lipitor if they make a very serious change in diet. Often the motivation is the unpleasant side effects they experience from the drugs.
You are only 33, it would be wise to find a way to the future without drugs.
But you may have to be motivated both for a true dietary change as well as for stopping the smoking.